Some embodiments described herein relate generally to virtual chassis, and, in particular, to methods and apparatus for increasing number of physical switches in a virtual chassis.
A virtual chassis allows two or more physical switches to interconnect with each other to form a unified single high bandwidth switch representing a single network element. Each physical switch includes one or more packet forwarding engines (PFEs) that are configured to perform traffic forwarding across the physical switches. Some known virtual chassis use a link-state routing protocol to decide a shortest cost path between a pair of PFEs across physical switches. In such virtual chassis, a global address is assigned to each PFE in the multiple physical switches. Thus, the number of PFEs and physical switches that can be included in a virtual chassis is limited by the number of bits in the global address assigned to a PFE.
Accordingly, a need exists for a virtual chassis that can support more number of PFEs than that can be globally addressed.